#div-frontend-login-overlay:after{
    content:''; /* Required to display content */
    position: absolute; /* Sets the position absolute to the top div */
    top: 0; 
    right: 100px;
    margin-left: -50px; /* Set margin equal to border px */
    width: 0;
    z-index:1;
    height: 0;
    border-top: solid 10px #fff; /* Creates the notch */
    border-left: solid 10px transparent; /* Creates triangle effect */
    border-right: solid 10px transparent; /* Creates triangle effect */
}